Method of reclaiming single base smokeless powder



dibutylphthalate.

Patented 'June 16, 1953 UNITED STATES, PATENT OFFICE METHOD OF REGLAIMING SINGLE BASE SMOKELESS POWDER Dwight A. Alderson, East Alton, Ralph Vincent Wakefield, Roxana, and Emerald P. Reichardt, Wood River, 111., assignors to Olin Industries, Inc., East Alton, 111., a corporation of Delaware No Drawing. Application August 9, 1950, Serial N0. 178,558

4 Claims. (Cl. 52-20) This invention relates to a process for reworking smokeless powder andmore particularly to a process for reclaiming the nitrocellulose content from single base smokeless powdershaving a substantial content of a modifier.

Government surplus cannon powders known as non-hydroscopic (NH), and flashless nonhydroscopic (FNH) smokeless powders and powdersflknown to the trade as IMR type, such as cal .30, cal. .50, and 20 mm. have as their base nitrocellulose of about 13.2% nitrogen content. Nitrocellulose of such nitrogen content is well suited for use as 'a raw material for making smokelesspowders for sporting cartridges. However, such types of smokeless powder are not readily reworked into sporting cartridge powder due to their high content of modifiers, e. g. NH

powder has about 8% dinitrotoluene and 4% When such type powders are used as the raw material in a process such as that set forth in US. 2,027,114, issued January 7, 1936, to Fredrich Olsen et' al., the resulting smokeless powder is dirty burning, that is to say, a residue of incompletely burned powder grains is left in the barrel'of the gun. This objectionable feature is believed toarise from the fact that the presence of deterrent materials within the resulting sporting powder grain inhibits theburning of such grains to the extent that anumber of the grains, or parts thereof, of a charge are not fully burned. In addition to this dirty burning effect the deterrent materials 'within the powder grain reduces the propellant power of the powder.

It is therefore an object of this inventionto provide a novel process for reworking such single base powders as are represented by the NH, FNH and 'IMR powders to provide a suitable base material for use in the manufacture of powder for sporting ammunition, military ammunition, and

the like. Another object is to provide a safe economical process for producing raw material for clean burning smokeless powders.

The foregoing objects and advantages as well 'as others which may become apparent from the detail description hereinafter are accomplished in accordance with this invention by treating the smokeless powder to be reclaimed in a mix- It has been discovered and water, a portion of the modifying material tinned objectionable features are eliminated. By

particulate powder as used herein is meant single base cannon powders as exemplified by the 20 mm., FNI-I and NH types ground to a particle size of not more than about 10% held in a standard U. 5. 0.070 inch screen and ground or unground .30 cal. and .50 cal. IMR type powder having a relatively high content of dinitrotoluene and dibutylphthalate, or similar modifiers. The treated particulate powder is then a source of clean, high nitrogen cellulose suitable for use as a raw material for the manufacture of smokeless powders by processes such as that set forth in the aforementioned U. S. Patent 2,027,114.

In carrying out the process the cannon powder is preferably ground in a water slurry to a particle size substantially within the range of about 0.07 inch to 0.004. inch in diameter. The particulate powder is then agitated in a mixture of from about 4 to 8 parts benzol and a minimum of 2 parts water per part of powder at a temperature in the range from 30 C. to the boiling point of benzol but preferably not above about 65 C. for a period of at'least four hours duration. At the end of the treatment the powder is separated from the aqueous benzol emulsion by any suitable means such as decantation, centrifuging or vacuum filtration. Any residual benzol adhering to the separated powder, which in some instances may be as high as 0.7 part benzol per part powder, may readily beremoved by again adding a minimum of about 2 parts water per part of powder and heating the slurry to a ternperature around the boiling point of water, for example 99 (3., while permitting the benzene to escape from the system. The water wet powder may then be dried, if desired, or may be utilized the water wet condition as the nitrocellulose for the process set forth in the aforementioned U. S. Patent 2,027,114. It is not essential that the treatment with aqueous benzol completely remove the modifier content which is ordinarily composed of dinitrotoluene and dibutylphthalate,

} but the duration of the treatment should be such 7 tion the powder is properly conditioned for conversion into smokeless powder of satisfactory burning characteristics. It is preferableto carry out the treatment in two or more steps. For example, the first step may consist of a treatment of four hours duration after which the powder is separated from the benzol emulsion and the powder is then againtreated in a fresh mixture of benzol and water for another four hour peeach particle gets a more uniform treatment The water also tends to reduce the amount of benzol adherent to the powdergrains after .the treatment. However, an important function -of the water is to increase thesafety of -.-the operation. For example, if during the. treatment, for one cause or another, the benzol should take fire, the powder being treatedis not likely to be fired and the hazard is greatly minimized. In

the absence of the water, a benzol 'fiash would'abe followed by a firing of the powder being treated. Furthermore, the last traces of benzol are more difficultly removable in the absence of the water.

:Inrorderto further clarify the invention there follows 'a detailed description of -;a preferred embodiment thereof.

, Example I to a temperature of 65C. and maintained with vagitation at this temperature for about four hours. water-benzol emulsion is removed from the At the end of the four hour period, the

powder by vacuum filtration. A' fresh charge of benzol and water in the same ratios utilized above are then added to the powder in the .kettle and the mixture is again heated with agitation as V rapidly as possible to65 C. and the temperature maintained there for about four hours. 'The benzol-water emulsion is then removed from the powder as above by vacuum filtration. In order to remove the last traces of benzol from the filtered powder, about 2.5 to about 3.0 parts by weight of water are added to the powder. The

.mixture is then agitated as above and heated as rapidly as possible-to 99 C. and this temperature .is maintained for about to minutesito remove the benzene from the system. The mixture The mixture is is then cooled to .a temperature less than about C. and the water is removed from the powder by decantation or vacuum filtration. .Thepowder I may then be dried, if it is so desired, or it may be utilized in the water wetstate as the raw material for a process such as thatset forth in S.

,Patent 2,027,114. I

As ,an illustration of the efiectiveness of such treatment, the powder before treatment. had an ether extractable content of about.13;5%, wherea as after the treatment the. ether extractable con= .tent was only about 1.4%. The ether extractable content of the untreated powder includedabout 8.6% dinitrotoluene and about 3.8% dibutylphthalate.

Example II In another embodiment the powder was treated {as describedin theforegoing example with the .exception that B-parts .of benzol-Were .used for 4 each part of powder instead of four parts, and in this instance the treated powder had a residual ether extractable content of about 1.6%.

Example III 1 'In still another embodiment the powderwas "In-still another embodiment the powder was treated as set forth in Example 1 except that the benzol to-powdenratio was about 3 to 1, instead of 4'to l, and only a single treatment was given ,withthe. emulsion at a temperature'ofGO" C'. The treated powder then had an ether extractable content of about 1.7

As illustrated ,in the .,f reeoin embodim n inven ion.ac mp ishe 'iw p p s f u stantially reducingthe'modifier content of the treated powderand the treated powderis then in a suitable condition for reprocessing. If amountsof benzol greater than about 8 parts to 1 part of. powder are, utilized, no appreciable benefit is effected in the treatment and the process becomes .uneconomical .and .,more hazardous. 'Amountsof benzol substantially less than 4 parts to .1 part ,of powder are not satisfactoryfrom the standpoint of removing the undesirable modifiers nd reconditionin the p wde f less tha about 4 parts benz larenutilized,the number of extractionsmust be, increased and even then one cannot be, certain of obtaining a useful. product. However, while certain specific details are set forthherein, it should be understood that. con- .siderable modificationcanbemade without depa ting from the sp iten s pe o th nvention.

. H vin thu esoribed he inventi n Wbatis cla me and d sired-ma num b laette Pa ent is:

1. .The .method v.of reclaiming. single base smokeless powderjcontaining benzol-soluble modi fiers which consists in dispersingthepowder in ;particulate form in a mixture composed essentially. of benzol and water, agitating thelmixture ,at an :elevated temperature until ,a .,subs t antial portion. of the modifier .contentis dissolved, re- ;moving the benzol-water mixture from the powder, adding water to the powderand heating until the ,residual benzol. isremoved from. the powder and thereaftercooling the mixture.

'2. The method of reclaiming single base smokelesspowder containing benzol-soluble modifierswhich consists iindispersing the powder in -:particulate form in a -mixtur-e composed essentially. of about four to eight parts benzol and a ..-minim. um of about-two parts water per part of powder -at.,a.,temperatureinthe range fromabout 30 C. .to the boil-ingapoint-of the benzol agitating the mixture for at .least aboutsfour -hours,-separating .the powder from. the 'benzolewater mixture, adding water to the powder .and l fiating .with agitat o fth mi ture t atemneratu ie ;near .theboiling point of water untillthe residual -benzo'l is removed. from th .poWder...and.ther-eaftiercoolingthe, mixture. 7 p .3. The. methodpf .rec aimig si i e as mokeless powder. c ntainin -jhem'q esolu l .mqil fi x wh chicon ist ii .disp mingjt epW e i pa ..ticulaterqrm a mixtur c mp sed e all of about four parts benzol and about two parts water per part of powder at a temperature of about 65 C. for a period of about four hours and then separating the powder from the benzolwater mixture, repeating said treatment until the modifier content of said powder has been reduced to less than about 2% by weight of the powder, dispersing said powder in Water and heating the mixture to a temperature near the boiling point of th water until the benzol is removed from the powder and thereafter cooling 10 the mixture.

4. The method of reclaiming single base smokeless powder containing benzol-soluble modifiers 'by dispersing one part of powderin particulate 15 2,123,517 form in a mixture composed essentially of at least 2151494 four parts of benzol and at least two parts of water at a temperature below the boiling point of the benzol with agitation for at least four hours, removing the benzol-water mixture from the powder, adding water to the powder and heating until the residual benzol is substantially removed from the powder.

DWIGHT A. ALDERSON.

RALPH VINCENT WAKEFIELD.

EMERALD P. REICHARDT.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,439,656 Woodbridge Dec. 19, 1922 1,666,049 Tozier Apr. 10, 1928 Woodbridge July 12, 1938 Ball Mar. 21, 1939 2,175,212 Olsen et a1 Oct. 10, 1939 

1. THE METHOD OF RECLAIMING SINGLE BASE SMOKELESS POWDER CONTAINING BENZOL-SOLUBLE MODIFIERS WHICH CONSISTS IN DISPERSING THE POWDER IN PARTICULATE FORM IN A MIXTURE COMPOSED ESSENTIALLY OF BENZOL AND WATER, AGITATING THE MIXTURE AT AN ELEVATED TEMPERATURE UNTIL A SUBSTANTIAL PORTION OF THE MODIFIER CONTENT IS DISSOLVED, REMOVING THE BENZOL-WATER MIXTURE FROM THE POWDER, ADDING WATER TO THE POWDER AND HEATING UNTIL THE RESIDUAL BENZOL IS REMOVED FROM THE POWDER AND THEERAFTER COOLING THE MIXTURE. 